The invention concerns fastening means of the type referred to in the field as clips. Such clips are used in holes of different types in a wide variety of construction elements. Clips are very common in the motor vehicle industry and are used, for example, to secure panels, but also various types of functional elements, for example cables, pipe conduits of various kinds, etc.
Clips also occur in various types of safety arrangements, for example for supporting vital parts in safety arrangements which deploy automatically in the event of collision, for example in airbags.
Clips of the type in question are input goods. Such goods have to be competitive in terms of price and satisfy stringent requirements in terms of uniform quality, and they must also meet stringent demands in respect of strength, stability and handling.
Clips made in one piece from plastic material or the like are very common. The material of the clip is chosen so that, in addition to the required mechanical stability/strength, the material also permits a certain degree of elastic resilience in areas of the clip where a kind of hinge or bridge is formed between material parts. A number of different types of clips made in one piece are already known in which heel-like elements interact with the stem of the clip via a hinge formed as a torsion hinge. These heels can be pivoted with elastic resilience into a recess in the clip stem. On assembly, the stem of the clip is quite simply pressed into a corresponding hole, the heels automatically swivel in and thereafter return to their original position, bearing against the underside of the object in which the hole is made.
Clips of said type are usually injection-moulded in multi-compartment tools or cast in a mould. The plastic material is preferably a thermoplastic, for example various types of acetal plastics, polypropylene, polyamide and the like are used. It is also possible to use thermosetting plastic.
The object of the invention is to further improve clips of said type by providing the possibility of optimum dismantling of the clip. This optimum dismantling entails that clips can be dismantled without any weakening whatsoever and can then be reinserted again into the same hole or some other corresponding hole.
For maintenance work and replacement of parts, for example in vehicles, clips are made available which permit non-destructive dismantling.
The novel clip construction makes it possible, as before, to produce the novel clip construction in the form of a clip made integral with a functional construction element. In accordance with an aspect of the present invention, a dismountable clip is provided. The clip includes a stem part, an entry end, and a hole edge attachment end, intended for insertion into a hole. The stem part has protruding heel-like elements which can be pivoted in and back out elastically. In a recess in the stem part, each heel-like element has a maneuvering shoulder at a distance inwards from a hinge connecting the heel-like element and the stem part. An axial hole for receiving a dismounting tool is formed through the hole edge attachment end and the stem part to the maneuvering shoulders. A free space is situated between the maneuvering shoulder and the entry end to allow the maneuvering shoulder and, hence, the heel-like element to be pivoted with the dismounting tool about the hinge in the direction towards the entry end.
In accordance with another aspect of the present invention, a method of producing a dismountable clip is provided. In accordance with the method, the clip is made in a divided mould tool, and the dividing plane of the mould tool is chosen such that it lies centrally in opposite sides of the stem part lacking heel-like elements. In addition, the axial hole extending to the maneuvering shoulder and the recess in the stem part are formed using the divided mould tool, using core pulling.
In accordance with a further aspect of the present invention, a method of dismounting a dismountable clip is provided. In accordance with the method, a rod-shaped dismounting tool is introduced into the axial hole in the stem part as far as the maneuvering shoulder. The end of the tool is engaged with the shoulder. The shoulder is pivoted towards the entry end, about the hinge, down into the free space between the maneuvering shoulder and the entry end. A gripable part of the hole edge attachment end or the stem part is thereafter gripped manually or with a tool, and the clip is removed without any interference from the heel-like elements.